There is a continual need for tamper evident seals for a carton. This is the case since the incidents of product tampering have been increasing. As a result, consumers are reluctant to purchase a product if it is not packaged in a way where it is very noticeable that a product has been the object of tampering. Also, merchants review their products and remove those that appear to have been objects of tampering. This has placed a demand on the development of effective tamper evident packaging.
A common way to make a carton, such as a carton that would contain a tube of a dentifrice, medicant or food, tamper evident is to seal the flaps with an adhesive and usually a hot melt adhesive. In order to open the carton and remove the tube, a person has to rip off one or more of the end flaps or at least alter them to the extent that is quite obvious that the carton has been opened. Also, it is necessary that the altering be such that once opened the carton cannot be readily resealed. That is, the carton cannot be resealed so as to disguise the fact that the carton has been opened. When the end flaps are adhesively sealed upon opening the carton is so altered that it cannot be resealed. Parts of the fiberboard of one flap are attached to another flap. The carton has been irreversibly altered.
However, there is a problem posed with some of the new carton materials. This particularly is the case with polymer coated fiberboard. Such a carton can have a high gloss finish and will be better able to weather moist and high humidity conditions. Also, the cartons have a neater and high quality performance. The problem is that adhesives do not readily adhere to such materials. This results in fake openings of the cartons from normal handling, and when purposely opened, the carton flaps are not sufficiently altered so as to be able to resealed. This problem is solved by the present invention. The solution is to provide at least one seal flap with at least one aperture so that adhesive will flow through such aperture and spread out below the aperture and in contact with one or more lower flaps. The lower flap or flaps will have one or more recesses to aid in the spreading out of the adhesive below the seal flap. At least one top flap then overlaps the at least one seal flap, with the lower surface of the seal flap having a fiberboard surface. That is, it does not have a polymer coated surface. The net result is that to open the carton the lower surface of the top flap and the seal flaps are permanently altered. They cannot be returned to their original sealed condition. Part of the fiberboard on the lower side of the top flap has been torn away and the apertures of the seal flaps have been damaged. When such a carton has been opened, it is very clear that it has been opened.
Although the use of apertures in flaps for the flow of glue through the flaps for better anchoring of the flaps together is shown in the prior art, such as in U.S. Pat. No. 837,324 and U.S. Pat. No. 2,084,106 and USSR Patent 914,416, there is not shown the presence of recesses in lower flaps so that the adhesive that flows through the apertures can spread out and better anchor to the lower flap. When the adhesive spreads out after flowing through an aperture, it cannot be pulled back through the aperture Also, the glue better adheres to the underside of the flap with the aperture.